1. Field of the Invention
The present invention relates to an arrangement for cooling in a controlled manner a rolled wire from rolling temperatures. The arrangement particularly includes a cooling unit, for example, water ramps, arranged following the finishing stand, a coiling unit for the wire and a cooling and conveying system for the spread-out wire coils.
2. Description of the Related Art
Wire is rolled in a rolling mill train in which the initial material, for example, a rod-shaped semi-finished steel having a cross-sectional area of 100 mm to 150 mm, is conveyed from a holding furnace to the rolling mill stands of a blooming train. The material rolled in the blooming train is subsequently rolled into round material in an intermediate train and a finishing train. The round material is then deformed thermomechanically in a multiple-stand roll series into an endless rolled material having a diameter of approximately 5.5 mm. The finished wire arriving from the finishing roll series is supplied directly from the rolling heat to the Stelmor cooling line which is used predominantly. In the Stelmor cooling line, the wire is cooled in a controlled manner in order to obtain certain material properties, i.e., a uniform physical quality of an entire length of the rolled wire and, thus, a good drawing property. Following the finishing stand series, the wire initially travels through water cooling stretch and is then stretched out on a conveyor system by means of a coiling unit. The wire is further cooled in a predetermined manner during the transport to the coil collector by means of blower air. The conveyor system either is a chain conveyor or a roller conveyor under which the cooling blowers are arranged in sections which are spatially separate from each other. The cooling air is blown from underneath through slots in the conveyor system. In the case of high-carbon steels, the temperature of the entering coils is 800.degree. to 850.degree. C., and in the case of low-carbon steels, the maximum temperature is 900.degree. C. In the case of low-carbon steels, the coils are conveyed as slowly as possible and without cooling air. In the case of high-carbon steels, the coils are conveyed with a high conveying speed and with maximum cooling air supply.
German patent 25 36 236 discloses a cooling and conveying arrangement for wire which is spread out by a coiling unit, wherein the conveying arrangement includes individual transporting sections with adjustable transporting speeds. The length of the successive transporting sections of the conveying arrangements are dimensioned for the desired temperature drop within each section occurring with the greatest possible wire dimensions. The temperature of the wire loops is determined by means of a radiation pyrometer at the end of each conveying section.
In previously known cooling and conveying arrangements for finished wire to be spread out by means of a coiling unit, cooling of the wire is regulated in a relatively complicated manner in order to obtain, as mentioned above, certain material properties of the wire, particularly with respect to the quality of the wire surface. One of the prerequisites for this is that the coiling unit must operate synchronously with the finishing stand series of the rolling mill train, so that no pulling or pushing forces occur and the wire can be placed in uniform spread-out coils on the subsequent conveyor system by means of the placement head. For this reason, the downwardly inclined coiling unit is of robust construction and has a particularly stiff housing in order to avoid natural vibrations. The placement tube is also of stable construction and is shaped and assembled in such a way that it can be easily blown out and a quiet wire guidance is ensured.
However, it has been found in some cases that certain tolerances in the placement tube of the coiling system, different placement speeds, different wire qualities, different wire dimensions and the like lead to a laterally displaced spreading out of the wire with the result that the wire coils are no longer placed centrally on the conveyor system. This may cause the wire coils to be placed with a deviation from the center of 50 to 150 mm. The wire coils are then pushed against the lateral guide surfaces of the conveyor. As a result, the wire surface is damaged and the wire coils are pressed into an oval shape with all negative consequences in the subsequently arranged coil collector. In some rolling mills it has been attempted to counteract this deficiency by providing partially movable guide surfaces on the conveyor system for pushing the placed wire coils back to the center of the conveyor system. However, these measures were also only able to incompletely prevent damage to the wire surface and oval shapes of the wire coils.